1. Field of the Invention
The present invention relates to a manufacturing method of circuit modules which electrically connects an electronic component to a substrate by utilizing laser beam, and relates to a manufacturing apparatus of circuit modules which is suited for carrying out the above method.
2. Description of the Prior Art
Japanese Patent Application Laid-Open No. 4-314390 discloses a method for mounting an electronic component on a substrate by utilizing a laser beam. Speaking concretely, this patent application discloses a method which loads an electronic component on a substrate so that an external electrode of the component is brought into contact with a cream solder preliminarily applied to a surface of a land and electrically connects the external electrode to the land by way of the solder by irradiating with a laser beam for the cream solder and melting it.
Since this method irradiates the cream solder with the laser beam after the electronic component is loaded on the substrate so that the external electrode of the electronic component is brought into contact with the cream solder preliminarily applied to the surface of the land, it is incapable of directly irradiating the cream solder applied to areas which are sandwiched and shaded by the external electrode and the land.
In other words, this method has a defect that it allows the cream solder to remain unmelted on the areas which are sandwiched and shaded by the external electrode and the land, thereby causing improper connections due to insufficient connecting areas and strengths.
This defect can be corrected to a certain degree by setting an energy (a product of a power multiplied by an irradiation time) of the irradiating laser beam at a high level. When the power of the laser beam is strengthened, however, the electronic component is subjected to bad thermal damage, thereby posing problems of degradation in qualities and variations of characteristics. When the irradiation time of the laser beam is prolonged, on the other hand, each component requires a longer connecting time, thereby making it impossible to accelerate manufacturing of circuit modules.
A primary object of the present invention is to provide a manufacturing method of circuit modules which solves the problem of improper connection and permits favorably connecting electronic components with a laser beam, and a manufacturing apparatus of circuit modules which is capable of securely carrying out this method.
To attain this object, the manufacturing method according to the present invention comprising steps of melting a connecting material preliminarily disposed on electrodes of a substrate by an energy of an irradiating laser beam, and loading an electronic component on the substrate so as to press electrodes of this component to the melted connecting material before the melted connecting material hardens.
This method is capable of solving the problem of the residual unmelted connecting material by sufficiently heating and melting the connecting material on the electrodes of the substrate with the irradiating laser beam, thereby making it possible to connecting the electrodes of the component to the electrodes of the substrate with connecting materials which are sufficiently heated and melted.
On the other hand, the manufacturing apparatus according to the present invention comprises a component loading device having an adsorbing nozzle which absorbs an electronic component and loads it on a substrate, a laser beam irradiation device which irradiates a laser beam to a connecting material preliminarily disposed on an electrode of the substrate, and a control device which controls the component loading and the laser beam irradiation so that the electrodes of the electronic component are pressed to the melted connecting materials after the connecting materials are melted by an energy of the irradiating laser beam and before the melted connecting materials harden.
This apparatus is capable of securely carrying out the manufacturing method described above with the component mounting device, the laser beam irradiation device and the control device which controls the former two devices.
The object described above, other objects, features and advantages of the present invention will be apparent from the following description and the attached drawings.